GPS (Global Positioning System)

Editor's Notes

1. GPS Any Time, Any Place, Right Time, Right Place
2. History of the GPS Basic Introduction How GPS work Characteristics of GPS Segments of GPS GPS MAPS Applications Advantages and Disadvantages
3. History of the GPS Developed by US Department of Defense • 1969—Defense Navigation Satellite System (DNSS) formed • 1973—NAVSTAR Global Positioning System developed • 1978—first 4 satellites launched
4. • 1993—24th satellite launched; initial operational capability • 1994—full operational capability • May 2000—Military accuracy available to all users
5. Global Positioning System It is a technique by which the location of any object, velocity, direction and time can be known precisely at any time. Whether the object is on the ground, on the sea water surface or in the air. GPS was invented by the United States Department of Defense.
6. The actual name of GPS is NAVSTAR (Navigation System with Time And Ranging) . This system becomes fully operational in 1994.it was invented by Roger L. Easton.
7. The GPS system consists of 24 satellites (32now) placed in near circular orbits arranged in 6 orbital planes at 55 degree inclination to equator at 20,200KM height orbital radius. The period of revolution is 12 hours. So that at least 4 satellites are available for observations at any time throughout the year anywhere on the world.
8. How GPS works GPS is based on satellite ranging, i.e. distance from satellites …satellites are precise reference points …we determine our distance from them if we are lost and we know that we are 11,000 miles from satellite A… we are somewhere on a sphere whose middle is satellite A and diameter is 11,000 miles
9. Distance measurements from two satellites limits our location to the intersection of two spheres, which is a circle.
10. A third measurement narrows our location to just two points.
11. A fourth measurement determines which point is our true location
12. Characteristics of GPS Free Accurate Reliable All weather Anytime & anywhere Unlimited user capacity
13. Segments of GPS Space Segment Control Segment User Segment
14. Three Segments of the Global Positioning System The Global Positioning System is comprised of three segments: the Control Segment, Space Segment and User Segment. Satellites (space segment) Receivers (user segment) Ground stations (control segment)
15. Space Segment GPS satellites fly in circular orbits at an altitude of 20,200 km and with a period of 12 hours. Orbital planes are centered on the Earth. Each satellite makes two complete orbits each sidereal day. It passes over the same location on Earth once each day. Orbits are designed so that at the very least, six satellites are always within line of sight from any location on the planet. The satellites continuously send radio signals towards earth. These radio signals are picked up by GPS receivers.
16. Control Segment The Control Segment consists of 3 entities: Master Control Station Monitor Stations Ground Antennas Control stations continuously track satellites, and update the positions of each satellite.
17. GPS Monitoring Station
18. Strategic Locations
19. User Segment The user's GPS receiver is the User Segment of the GPS system. GPS receivers are generally composed of an antenna, tuned to the frequencies transmitted by the satellites, receiver-processors. They include a display for showing location and speed information to the user. A receiver is often described by its number of channels this signifies how many satellites it can monitor simultaneously.
20. SEGMENTS OF GPS In detailed
21. There are three types of segment Space segment Control segment User segment
22. Space segment The main functions of the Space Segment are to transmit radio-navigation signals, and to store and retransmit the navigation message sent by the Control Segment. These transmissions are controlled by highly stable atomic clocks on board the satellites
23. The GPS Space Segment is formed by a satellite constellation with enough satellites to ensure that the users will have, at least, 4 simultaneous satellites in view from any point at the Earth surface at any time. The nominal GPS satellite constellation consists of 24 space vehicles (SVs) distributed in six orbital planes with an inclination of 55 degrees in relation to the equator. In addition, the constellation has 3 backup satellites.
24. Orbits are nearly circular, a semi-major axis of 26 560 km, at a height of 20 200 km .The satellites have a speed of 3.9 km per second and a nominal period of 12 h sidereal time (11 h 58m 2 s), The present configuration allows users to have a simultaneous observation of at least 4 satellites in view worldwide, with an elevation masking angle of 15 deg.
25. Control segment The GPS control Segment (also referred to as ground Segment or Operational Control System) is the responsible for the proper operation of the GPS system. The GPS Control Segment is composed by a network of Monitor Stations (MS), a Master Control Station (MCS), a backup of the MCS and the Ground Antennas (GA).
26. The Master Control Station (MCS) processes the measurements received by the Monitor Stations (MS) to estimate satellite orbits (ephemerides) and clock errors, among other parameters, and to generate the navigation message. These corrections and the navigation message are uploaded to the satellites through the Ground Antennas, which are co-located in four of the Monitor stations (Ascension Island, Cape Canaveral, Diego Garcia, and Kwajalein).
27. Control Segment .The main tasks performed by the CS are the following: Monitoring and control of satellite orbital parameters; Monitoring health and status of the satellite subsystems (solar arrays, battery power and the level of propellant used for maneuvers);
28. Activation of spare satellites; Update of parameters in the navigation message (ephemeris, almanac and clock corrections); Resolving satellite anomalies; Controlling Selective Availability (SA) and Anti-Spoofing (A/S) Passive tracking of the satellites.
29. The Ground Segment is comprised of four major subsystems: Master Control Station (MCS, soon to be replaced by a New Master Control Station [NMCS]) Backup Master Control Station (BMCS, soon to be replaced by an Alternate Master Control Station [AMCS]) Network of four ground antennas (GAs), Network of globally-distributed monitor stations (MSs).
30. The Master Control Station Located at Colorado Springs, the Master Control Station (MCS) is the central control node for the GPS satellite constellation. The MCS is responsible for all aspects of constellation command and control, to include Routine satellite bus and payload status monitoring. Satellite maintenance and anomaly resolution.
31. Monitoring and management of Precise Positioning Service (PPS) Signal-In-Space (SIS) performance in support of all performance standards. Navigation message data upload operations as required to sustain performance in accordance with accuracy and integrity performance standards. Detecting and responding to PPS SIS failures.
32. Master control station over the world
33. The Monitor Stations They are distributed around the world and equipped with atomic clocks standards and GPS receivers to continuously collect GPS data for all the satellites in view from their locations. The collected data is sent to the Master Control Station where it is processed to estimate satellite orbits (ephemerides) and clock errors, among other parameters, and to generate the Navigation Message.
34. Prior to the modernization program, the Monitor Stations network comprised five sites located in: Hawaii, Colorado Springs (Colorado, US), Ascension Island (South Atlantic), Diego Garcia (Indian Ocean), Kwajalein (North Pacific).
35. In order to increase performance and accuracy, new stations were incorporated into the ground segment providing greater visibility of the constellation: Cape Canaveral (Florida, US) was incorporated in 2001 and six new stations in 2005: Adelaide (Australia), Buenos Aires (Argentina), Hermitage (UK), Manama (Bahrain), Quito (Ecuador) Washington DC (USA).
36. Five more stations were added afterwards in 2006: Fairbanks (Alaska), Osan (South Korea), Papeete (Tahiti), Pretoria (South Africa) Wellington (New Zealand).
37. With this configuration, each satellite is seen from at least three monitor stations, which allows computing more precise orbits and ephemeris data, therefore improving system accuracy.
38. Monitor station over the world
39. The Ground Antennas The Ground Antennas uplink data to the satellites via S-band radio signals. These data includes ephemerides and clock correction information transmitted within the Navigation Message, as well as command telemetry from the MCS. This information can be uploaded to each satellite three times per day, i.e., every 8 hours; nevertheless, it is usually updated just once a day.
40. The ground antennas are co-located in four of the Monitor stations: Ascension Island Cape Canaveral Diego Garcia Kwajalein
41. The Ground Antennas
42. User segment The GPS User Segment consists on L-band radio receiver/processors and antennas which receive GPS signals, determine other observables, and solve the navigation equations in order to obtain their coordinates and provide a very accurate time.
43. The GNSS Market Report, Issue 3, provided by European GNSS Agency, has estimated that the number of GPS enabled devices in 2012 were about two billion units.
44. What does a GPS receiver do? GPS receiver allows you to pinpoint your location, anywhere in the world, based on latitude and longitude coordinates. It can tell you in what direction you are heading. It can show you: how fast you are going your altitude a map to help you arrive at a destination
45. GPS MAPS
46. Types of GPS maps Raster Maps Vector Maps Android maps
47. Raster Maps :- This mapping is usually scanned form paper version , and is called raster mapping Raster because it is made up of collections of pixels .
48. Raster map
49. Uses of raster Maps Programs such as :- 1) Trax 2) Fugawi 3) National Geographic 4) Maptech , etc .
50. 2) Vector Maps :- In vector maps the features are recorded one by one, with shape being defined by the numerical values of the pairs of x y coordinates.
51. Vector Map
52. Difference between raster map and vector map Vector relatively low data volume faster display can also store attributes less pleasing to the eye Raster relatively high data volume slower display has no attribute information more pleasing to the eye
53. RASTER VECTOR
54. Android maps used by GPS Types of maps used by android maps Street maps Topographic maps Aerial photography
55. Street Maps A street map is a map of a town or city , showing the locations and names of all the streets and roads for navigation .
56. Topographic Maps Topographic maps or topo maps is a detailed and accurate graphic representation of cultural and physical features of the earth such as mountains , rivers , forests etc .
57. Aerial photography An aerial photography is any photo captured above the ground . Aerial photography is mainly used in military operation , it is considered as an important map substitute in the global positioning system technology .
58. Applications
59. GPS answers five questions Where am I? Where am I going? Where are you? What is the best way to reach there? When will I reach there?
60. Applications Civilian Applying location coordinates to digital objects such as photographs Disaster Relief/Emergency Services Vehicle Tracking Systems Person Tracking Systems GPS Aircraft Tracking Telematics: GPS technology integrated with computers and mobile communications technology in automotive navigation systems.
61. USE OF GPS GPS LOCATION Where am I? Navigation Where I am going. Tracking Monitoring as its moving along Timing When will all happen? Mapping Where is everything else?
62. Use of Gps or Application Gps technology has matured into a resources that goes far beyond its original design goals. Now a days people are using gps in ways that their work more Productive, safe and easier. Location Navigation Tracking Mapping and survey Timing science
63. Location Gps is useful for finding location of any object lying on the ground , on the sea surface or in the air at any time in any weather conditions.
64. LOCATION
65. LOCATION
66. Navigation Gps helps us to determine exactly where we are , but sometimes it is more necessary to how to get somewhere else. Gps was originally designed to provide Navigating on water, air and land. GPS technology is also useful for transportation management and bearthing Of ships at docks.
67. NAVIGATION
68. NAVIGATION
69. Tracking Gps technology is also useful for monitoring vehicles and persons. Tracking is useful in the following matters: Mass transit Ship tracking Vehicle tracking Gps tracking is widely used by police, ambulance and fire Department.
70. Mapping and survey by using Gps, maps regarding mountains, rivers, forests, Tower etc. Conservation of natural resources Precious minerals Preservation of scare animals Forest monitoring Managing effects of damage and disasters. Weather forecasting. Geodetic surveying etc. .
71. MAPPING AND SURVEY
72. Timing Gps can also used to determine precise time , time intervals and frequency. Gps satellites Carry highly accurate atomic clocks. And in order for the system to work, Gps receivers on The ground synchronize themselves to these clocks . Therefore, ever gps receiver also Contain atomic clock. Gps timings are useful for:
73. Astronomers Computer networks Communication system Radio and television system Banks Power companies, etc.
74. Science Archaeology Atmospheric Science Environmental Geology & Geophysics Oceanography Wildlife
75. Public Safety Environmental resource management Local planning Surveying Military applications Navigation Tracking Missile Guidance
76. Military use of GPS
77. Aviation GPS technology is being applied in aircraft safety systems, air traffic control system, and zero visibility landing. GPS technology can be used to plot aircraft altitude to a pitch of one tenth of one degree. In future, it is expected to reduce the number of people required in the control tower and cockpit.
78. Tracking of wild animals Animals are equipped with gps receivers and with wireless transmitters. The gps determined position is transmitted to the control station. This information is used to track animals and for studying their nomadic patterns.
79. Other Applications…
80. Aerial Photography
81. Topography map
82. Surveyors use GPS during surveying
83. Establish Waypoints at strategic locations The GNSS Receiver “Connects the dots” Area and perimeter measurements are generated
84. Example of GPS survey
85. GNSS supported applications are literally supporting applications that range from entertainment to food product, to emergency services, to transportation. It is impacting us in ways that we do not even know about...
86. Advantages of GPS The most popular advantages of GPS tracking device is when it is used as a vehicle navigator. If your car or boat has a GPS tracking device, you will be able to determine exact location, speed, direction and time GPS works on day and night for 24 hours continuously
87. GPS is useful for finding location of any object lying on the ground, on the sea surface or in the air at any time in any weather conditions. GPS works even if the points are not intervisible. Manpower requirement is very less. All weather operation is possible. Time required for determining position of object is very less.
88. Accuracy level is very high. Good GPS gives accuracy of about 10mm. If your vehicle is ever stolen the GPS system will track the vehicle and the authorities will be able to get it back in no time.
89. Advantages Fast speed leads u in right direction Helps improve mapping skills Makes navigation easier Has panic buttons built in You can be found easier if in danger or in accident Disadvantages Cellular devices can track other cellular device users Not very cheap People focus on GPS more than road =accidents Should be used as backup map but used as 1st resource Needs good care and handling External power
90. Thank You. I think it would be helpful for you to understand GPS. Prepared By: Shailesh Chauhan